The use of “round” wrapping or baling machines (hereinafter “baler”) for baling agricultural produce such as hay, straw, silage, or cotton into a “round” bale (referring to a generally cylindrically-shaped bale having a generally round cross-section) has become increasingly common in recent years. Due to at least financial and technical considerations, such round balers are replacing older systems of baling cubic-type bales, which have a generally square cross-section and are secured by different types of metal wire, sisal twine, or baling twine made from polypropylene or polyethylene. The first round-balers also used various types of twines to secure the bale. Over the years, however, different types of netting and plastic films have been used to wrap and secure square or round bales, thereby replacing the use of various types of securing wire or twine.
The use of netting, and in particular knitted Raschel netting, has become more common for wrapping bales of agricultural produce. Nettings, however, are primarily open, in that the knitted ribbons that make-up the netting only account for part of the surface area of the bale and do not protect the bales from forces of nature such as rain, humidity, snow, hail, or wind. Wrapping materials made from plastic films provide improved protection of the wrapped produce from the forces of nature, as it is common for agricultural produce to remain wrapped in an open field for a time period that could vary from several months to more than a year before use. One such plastic film is commonly known as “sticky film,” which includes plastic films that inherently cling to itself or plastic films that include an adhesive applied to the complete surface area of at least one side of the plastic wrap or across the entire lateral dimension, i.e., from lateral end to lateral end. With the adhesive disposed at the lateral edges and along the longitudinal length of such wrapping material, the ease and progress of the wrapping material through the baler is greatly impeded by frictional-type interference and jams that decrease productivity and increase cost. Other problems inherent with “sticky films” result from, for example, dusty conditions, moisture, or wind. Under these and other conditions, it is typical for the adhesive securing the tail end of the wrapping material to become loose after a short time. Once the tail end of a wrapped bale becomes loose, continued exposure to wind and moisture will cause the tail to flutter about and the wrap will ultimately unravel and break open, thereby minimizing precious storage time.
An additional disadvantage with the use of previously-known adhesive films is that the adhesiveness of the film is uniform on both sides or on one side only. Consequently, the accepted use is with materials with a given level of adhesion that is imparted during the manufacturing process of the wrapping material. It is possible to obtain materials that are adhesive on one side or both sides. In each of these cases, the entire surface area is adhesive and the level of adhesion is limited to the strength required to release the wrapping material from the roll of material. There are two distinct disadvantages with this method: (1) the limited level of adhesion, and (2) the adhesive is over the entire wrapping area.